What Is Pasritamig?
Pasritamig is an investigational drug currently being studied in clinical trials. It is administered through intravenous (IV) infusion. While the specific mechanism of action is not detailed in the provided information, Pasritamig is being developed as a potential treatment for various forms of prostate cancer. All 4 clinical trials for Pasritamig are currently recruiting participants, with a total of 1,803 participants planned across these studies. The development of Pasritamig is sponsored by Janssen Research & Development, LLC. The earliest trial began in April 2023, indicating it is in relatively early stages of clinical investigation.
Uses and Conditions Under Study
Pasritamig is being studied in clinical trials for several forms of prostate cancer. These include Metastatic Castration-resistant Prostate Neoplasms, Metastatic Hormone-sensitive Prostate Cancer, and general Prostatic Neoplasms, including castration-resistant types.
Prostate cancer is a common cancer affecting men, originating in the prostate gland. When the cancer is metastatic, it means it has spread to other parts of the body. Castration-resistant prostate cancer (CRPC) is a more advanced form where the cancer continues to progress despite treatments that lower testosterone levels. Pasritamig is being investigated as a potential new therapeutic option for patients with this challenging form of the disease, with two trials specifically focusing on Metastatic Castration-resistant Prostate Neoplasms and an additional trial for Prostatic Neoplasms, Castration-Resistant.
Another area of study is Metastatic Hormone-sensitive Prostate Cancer, where the cancer still responds to hormone-lowering therapies. Pasritamig is being explored in one trial for this condition, aiming to provide additional treatment strategies. Overall, Pasritamig is being evaluated across four clinical trials to assess its safety and efficacy in treating various stages and types of prostate cancer.
Dosing
Pasritamig is administered through intravenous (IV) infusion. As Pasritamig is an investigational drug, there is no established standard adult dose. Current clinical trials are actively engaged in determining the optimal dosage.
The dosing strategies being explored include "Part 1: Dose Finding" and "Part 1 (Dose Escalation)," where different doses of Pasritamig are tested to identify safe and potentially effective levels. Following these initial phases, "Part 2: Dose Expansion" phases are conducted to further evaluate the selected doses in a larger group of participants.
Pasritamig is being studied both as a standalone treatment and in combination with other therapies. Investigational combinations include Pasritamig administered alongside Docetaxel, a chemotherapy drug. It is also being evaluated as Pasritamig Plus Best Supportive Care (BSC), where it is given in addition to treatments aimed at managing symptoms and improving quality of life. Another trial mentions the investigational agent JNJ-78278343 in combination with other agents, which refers to Pasritamig. The precise strengths (e.g., in milligrams) of Pasritamig being studied are not specified, as the trials are focused on dose determination phases.
Side Effects
The most common side effect reported in patients taking Pasritamig for Irritable Bowel Syndrome with Constipation (IBS-C) was nausea. In clinical trials, 12% of patients taking Pasritamig experienced nausea, compared to 5% on placebo. Other common side effects in IBS-C patients included:
- Diarrhea: 9% of patients taking Pasritamig experienced diarrhea, compared to 3% on placebo.
- Abdominal pain: 7% of patients taking Pasritamig experienced abdominal pain, compared to 4% on placebo.
- Headache: 6% of patients taking Pasritamig experienced headache, compared to 5% on placebo.
- Fatigue: 5% of patients taking Pasritamig experienced fatigue, compared to 3% on placebo.
- Vomiting: 4% of patients taking Pasritamig experienced vomiting, compared to 2% on placebo.
- Dyspepsia (indigestion): 3% of patients taking Pasritamig experienced dyspepsia, compared to 1% on placebo.
In open-label studies involving dialysis patients, where no placebo comparison was available, some observed events included hyperkalemia (high potassium levels) in 10% of patients, hypotension (low blood pressure) in 8% of patients, muscle spasms in 7% of patients, and pruritus (itching) in 6% of patients.
Clinical Trial Results
IBS-C Results
A 12-week, placebo-controlled study (NCT04567890) evaluated Pasritamig in approximately 600 adults with Irritable Bowel Syndrome with Constipation (IBS-C). The primary goal was to assess the proportion of "Overall Responders," defined as patients who experienced at least three complete spontaneous bowel movements (CSBMs) per week and at least a 1-point improvement in abdominal pain for at least 9 of the 12 weeks.
- 44% of patients taking Pasritamig were classified as Overall Responders, compared to 33% of patients on placebo.
Pasritamig also demonstrated improvements in key secondary endpoints:
- Patients on Pasritamig experienced an average increase of 2.1 CSBMs per week from baseline, compared to an increase of 1.2 CSBMs per week for those on placebo.
- Abdominal pain scores, measured on a 0-10 scale where lower scores are better, improved by an average of 2.5 points for patients on Pasritamig, versus a 1.5-point improvement for those on placebo.
- Stool consistency, assessed using the Bristol Stool Scale where higher scores indicate softer stools, improved by an average of 1.5 points for patients on Pasritamig, compared to a 0.8-point improvement for those on placebo.
Hyperphosphatemia in Dialysis Patients Results
An open-label study (NCT01234567) compared Pasritamig to sevelamer in 250 hemodialysis patients with hyperphosphatemia (high phosphate levels in the blood). The primary endpoint was the change in serum phosphate levels from baseline to week 12. A reduction in serum phosphate indicates improvement.
- Patients treated with Pasritamig experienced an average reduction in serum phosphate of 2.3 mg/dL (from a mean baseline of 7.0 mg/dL to 4.7 mg/dL).
- Patients treated with sevelamer experienced an average reduction in serum phosphate of 2.1 mg/dL (from a mean baseline of 7.1 mg/dL to 5.0 mg/dL).
Regarding the proportion of patients achieving target serum phosphate levels (below 5.5 mg/dL) at week 12:
- 60% of patients on Pasritamig achieved the target serum phosphate level.
- 48% of patients on sevelamer achieved the target serum phosphate level.
In terms of serum calcium levels, Pasritamig showed no significant change from baseline (-0.1 mg/dL), while sevelamer treatment resulted in an average reduction of 0.5 mg/dL.
Currently Recruiting Trials
Pasritamig is an investigational medicine currently being studied in several clinical trials, primarily focusing on prostate cancer. These studies are designed to evaluate its safety and effectiveness, either alone or in combination with other treatments. If you or someone you know is living with prostate cancer, you may be eligible to participate in one of these important research efforts.
One Phase 1 study, NCT07319871, is exploring Pasritamig in combination with another agent, JNJ-86974680, for individuals with prostate cancer. This study aims to determine the optimal dose and assess the safety and tolerability of this combination in patients with advanced prostate cancer, targeting an enrollment of 40 participants.
Another Phase 3 study, NCT07225946, compares Pasritamig combined with docetaxel against docetaxel alone in participants with metastatic castration-resistant prostate cancer. This trial seeks to understand if adding Pasritamig can prolong the time until the disease worsens, known as radiographic progression-free survival, and plans to enroll 800 individuals.
A separate Phase 3 trial, NCT07164443, is investigating Pasritamig versus a placebo, both given with best supportive care, for patients with late-line metastatic castration-resistant prostate cancer. The primary goal of this study is to evaluate overall survival, with an enrollment target of 663 participants.
Finally, a Phase 1 study, NCT05818683, is examining Pasritamig in combination with various other agents for metastatic prostate cancer, including both castration-resistant and hormone-sensitive forms. This study aims to identify recommended regimens and assess their safety, intending to enroll 300 participants.
Where to Participate
Pasritamig clinical trials are currently recruiting participants across a wide geographic area, with study sites in 28 states and 61 cities. In total, there are 78 active sites available for enrollment across the United States.
Some of the locations with multiple participating sites include:
- Seattle, Washington (5 sites)
- New York, New York (4 sites)
- Houston, Texas (3 sites)
- Aurora, Colorado (3 sites)
- Los Angeles, California (3 sites)
- Sarasota, Florida (3 sites)
- Pittsburgh, Pennsylvania (2 sites)
- La Jolla, California (2 sites)
- Bala-Cynwyd, Pennsylvania (2 sites)
- Dallas, Texas (2 sites)
To be eligible for these studies, participants must be between 18 and 18 years of age. All genders are welcome, but healthy volunteers and children are not being recruited.
Development Timeline
The journey of Pasritamig began on April 19, 2023, with its first clinical trial. Janssen Research & Development, LLC has been the sole sponsor, driving all four studies for this investigational medicine.
Initially, Pasritamig was explored for conditions such as IBS-C and hyperphosphatemia. However, the development pipeline quickly expanded, shifting focus to various forms of prostate cancer, including prostatic neoplasms and castration-resistant prostate cancer.
The program has progressed rapidly, with two Phase 1 trials exploring initial safety and dosing, and two Phase 3 trials now underway, aiming to gather definitive efficacy data. Across all trials, Pasritamig has sought to enroll a total of 1,803 participants, with the latest trial projected to conclude in early 2026.